The invention relates to a medical or technical endoscopic instrument, comprising a shaft having an endoscope optical system arranged therein, which comprises a distal front face, and a working element also arranged in the shaft, wherein further the shaft serves to supply an irrigation fluid into an operation or application area.
A medical instrument of this kind is known from document DE-C-195 20 277.
By means of a medical instrument of the type mentioned at the outset, tissue in the human or animal body is treated with the working element, for example is removed, grasped and/or coagulated in minimally invasive surgery under endoscopic control with the endoscope optical system.
For treating tissue, a working element is used with at least one tool which is configured as a purely mechanically cutting tool, for example in the form of forceps jaws, or as an electrode supplied with high frequency current, with which tissue can be removed or cut or coagulated due to the action of high frequency current.
Such an instrument for medical purposes is known for example from the German catalogue of the firm Karl Storz GmbH and Co., Tuttlingen, xe2x80x9cKarl Storz-Endoskopexe2x80x9d, Vol. Urology, page RES-SC 6 A, Edition 1995.
The instrument known from the German catalogue mentioned at the outset is a resectoscope, where the various working elements having cutting electrodes, coagulation electrodes or curettes can be inserted with which the corresponding treatment can be carried out. The invention however is not limited to a resectoscope.
Endoscopic instruments of this type are also known for technical purposes, which are used in difficultly accessible spaces in machines, motors or the like.
Since bleeding naturally occurs when removing tissue, such instruments provide for the introduction of an irrigation fluid through the shaft into the operation area to irrigate away the blood which obstructs the view. The irrigation fluid is passed through the shaft from the proximal end to the distal end, where it exits from the distal end to irrigate the operation area in the region of the tool. Normally, an excess cross-section remaining in the shaft when the endoscopic optical system and the working element are inserted is usable as an irrigation cross-section. The irrigation fluid therefore flows in the shaft along the endoscope optical system and passes its front face.
The problem results with the irrigation fluid running along the endoscope optical system, that a dead space of flow is formed distally in front of the front face of the optical system, which is the light emission and the light inlet end of the endoscope optical system. This means that the irrigation fluid during irrigation does not reach distally in front of the front face of the optical system. Rather, blood and pieces of tissue can collect there, which are not reached by the irrigation fluid and are not washed away. However, the blood and tissue pieces collecting in front of the front face are non-transparent and thus obstruct visual control with the endoscope optical system. The problem of a dead space in the flow arises particularly for optical systems with a straight-forward view or oblique-forward view, whose front faces are nearly perpendicular to the flow direction of the irrigation fluid, i.e. when a perpendicular line to the front face makes an angle of about 0xc2x0 to about 20xc2x0 with respect to the flow direction.
The additional problem arises in instruments for treating tissue with high frequency current that small gas bubbles form when treating the tissue with high frequency current. These collect in the dead space of flow in front of the distal front face of the optical system and adhere to the front face and are not caught by the irrigation fluid and washed away due to the formation of the dead space of flow.
The instrument known from document DE-C-195 20 277 mentioned at the outset comprises a shaft, an endoscope optical system received therein and a working element also received in the shaft. In the remaining space between the shaft, the endoscope optical system and the working element, an irrigation fluid is conducted from the proximal end to the distal end. Flow-influencing means are provided for the purpose that the irrigation fluid reaches in front of the front face of the endoscope optical system. The flow-influencing means comprises an opening in the shaft and an outer shaft arranged about the shaft and spaced therefrom, wherein in the space between the outer shaft and the shaft, a vacuum is applied. The irrigation fluid conducted through the shaft to the distal end is sucked through the opening into the space between the outer shaft and the shaft, whereby the irrigation fluid is conducted along the front face of the endoscope optical system.
The object of the present invention is to provide an instrument of the type mentioned at the outset in which the handling of the instrument is improved.
According to the present invention, this object is achieved with respect to the instrument mentioned at the outset by an endoscopic instrument, comprising a shaft, an endoscope optical system arranged in said shaft, said endoscope optical system having a distal front face, and a working element arranged in said shaft, wherein said shaft serves to supply an irrigation fluid into an operation or application area, wherein flow-influencing means are provided such that said irrigation fluid reaches in front of said front face of said endoscope optical system, and wherein said flow-influencing means are provided on said working element.
The instrument according to the present invention, thus, provides suitable means for influencing the flow of irrigation fluid in the region of the front face such that at least a portion of the irrigation fluid is deflected in front of the front face and a fluid flow occurs in the dead space of flow formed in conventional instruments in front of the front face. Thus, the blood, tissue pieces and optionally gas bubbles which can collect in front of the front face and obstruct the view are caught by the irrigation fluid and washed away. The invention avoids the collection of non-transparent fluids or tissue pieces, in particular for endoscope optical systems whose front face is disposed perpendicularly or nearly perpendicularly to the flow direction and where a dead space of flow forms to greater extent. The flow-influencing means can be configured and arranged such that the otherwise substantially laminar flow in the region of the end face of the optics is converted into a turbulent flow and/or the flow direction of the flushing fluid can be deflected such that a flow component along the front face of the optical system is formed. In both cases, it is guaranteed that the front face is sufficiently irrigated with the irrigation fluid. According to the invention, the flow-influencing means are provided on the working element. The advantage is that the flow-influencing means can be configured and positioned such that they do not obstruct the view. Since the working elements are often arranged to be axially shiftable relative to the endoscope optical system, this configuration opens up the very advantageous possibility of providing different flow conditions by moving the working element back and forth to efficiently deflect the flushing fluid in front of the front face.
The object underlying the invention is thus completely achieved.
In a preferred embodiment, the flow-influencing means are configured as flow obstructions which cause a swirling of the irrigation fluid in front of the front face of the optical system.
The advantage is that a swirling of the irrigation fluid in front of the front face of the endoscope optical system effectively causes a mixing of the irrigation fluid with the blood collected in front of the front face and results in a very effective removal of adhering gas bubbles or pieces of tissue.
In a further preferred embodiment, the flow-influencing means are configured as flow deflection means which generate a flow component along the front face of the endoscope optical system.
This feature also is suitable for preventing a dead space of flow in front of the front face of the endoscope optical system, wherein the irrigation fluid in the region of the front face is deflected from its original, substantially axially directed flow direction, such that at least a partial flow is formed along the front face and the front face is thus effectively irrigated.
In a further preferred embodiment, the flow-influencing means comprise at least one flow element which comprises a surface against which the irrigation fluid flows, and which is inclined or runs transversely with respect to the flow direction.
The inclined or transversed surface, against which the fluid flows and which projects from the working element, leads to a swirling of the irrigation fluid in the region of the front face of the endoscope optical system in an advantageously constructively simple manner. The flow element or flow elements can be simply attached to the working element as an additional part, for example in the form of small rods, small plates, guide plates or the like.
The surface is preferably flat or has a concave curvature directed to an axis of the endoscope optical system.
When the surface is flat and inclined or transverse to the flow direction, this surface substantially acts as an impact surface leading to a swirling of the irrigation fluid. A deflection of the flow direction can be achieved with a concave curvature of the surface, such that the irrigation fluid flows along the front face of the optics.
In a further preferred embodiment, several flow elements are arranged axially and/or circumferentially distributed on the working element.
The feature has the advantage that a precise influence of the flow of irrigation fluid can be enhanced with several flow elements arranged and distributed on the working element. When the working element is axially movable, a further advantage is that sufficient irrigation of the space in front of the front face is guaranteed at different axial working positions of the working element.
In a further preferred embodiment, the working element has a forked section in a distal region, wherein two legs of the forked section run axially along the sides of the endoscope optical system and run together at a proximal unitary section, which extends axially adjacent to the endoscope optical system. The working element comprises a bend in the transition region from the forked section to the unitary section, which lies axially in the region of the front face of the optics in at least one axial working position of the working element.
Such a bend is provided in conventional working elements of this type, which normally serve as an electrode support for an electrode supplied with high frequency current. However, in these known working elements, the bend is proximally behind the front face of the endoscope optical system in every axial position of the working element relative to the endoscope optical system. In contrast, according to the configuration of the present invention, the bend of the working element, which is located in the approximately V-shaped transition region between the forked section and the unitary section, is configured such that the bend is located axially in the region of the front face of the optics at least in one position of the working element. Thus, the bend can advantageously be used as a flow-influencing measure for precisely affecting the flow of the irrigation fluid in the region distally in front of the front face of the endoscope optical system.
In a further preferred embodiment, the working element is axially shiftable relative to the endoscope optical system.
The advantage is that the intended influence on the irrigation fluid flow can be additionally enhanced by an axial back and forth movement.
In a further preferred embodiment, the working element is an electrode carrier, and the at least one tool is an electrode supplyable with HF current.
As already mentioned at the outset, the additional problem arises with high frequency instruments that the effect of high frequency power produces gas bubbles which adhere to the front face of the endoscope optical system. It is now advantageously achieved, through the flow-influencing means provided in the present invention, that the gas bubbles can also be washed away from the front face of the endoscope optical system through the intended influence on the irrigation fluid flow.
However, it is also preferred when the working element has a shaft with a mechanically acting tool. Blood can also collect in front of the front face of the endoscope optical system in conventional instruments which do not use high frequency power, because a dead space of flow forms there. This problem is also effectively eliminated by the invention, also for purely mechanical instruments through a precise influence on the irrigation fluid flow by flow-influencing means.
Further advantages can be taken from the following description and the appended drawings.
It will be understood that the above-mentioned features and those to be discussed below are applicable not only in the given combinations, but may also be used in other combinations or taken alone without departing from the scope of the present invention.
Selected embodiments of the invention are illustrated in the drawings and will be described in detail in the following.